The value of routine oxytocics to reduce postpartum haemorrhage after vaginal birth has been well established; their value in caesarean section has received little attention, but it has been assumed that the benefits also apply to caesarean section. Practice varies on the use of a bolus (UK, Australia, Europe), bolus plus infusion (UK if haemorrhage occurs), or infusion alone (in US).
This RCT determined the effects of adding an oxytocin infusion to bolus oxytocin on blood loss at elective caesarean section. It involved 2069 women with a singleton pregnancy at five maternity hospitals in the Republic of Ireland and was conducted from February 2008 to June 2010.
The intervention group received 5 IU oxytocin IV bolus and additional 40 IU oxytocin infusion in 500mL of normal saline administered over 4 hours (bolus and infusion group). The placebo group received the same bolus and a placebo infusion of normal saline solution (bolus only group). The main outcome measure was major obstetric haemorrhage (blood loss >1000 mL) and need for an additional uterotonic agent.
The following findings were reported:
• There was no difference in the occurrence of major obstetric haemorrhage between the groups (bolus and infusion 15.7% (158/1007) vs. bolus only 16.0% (159/994), adjusted odds ratio 0.98, 95% CI, 0.77 to 1.25, p = 0.86).
• The need for an additional uterotonic agent in the bolus and infusion group was lower than that in the bolus only group (12.2% (126/1033) vs. 18.4% (189/1025), 0.61, 0.48 to 0.78, p < 0.001).
• Side effects were not increased after use of an additional oxytocin infusion.
• Women were less likely to have a major obstetric haemorrhage in the bolus and infusion group than in the bolus only group if the obstetrician was junior rather than senior (0.57, 0.35 to 0.92, p =0.02).
The researchers conclude from these findings that “addition of an oxytocin infusion after caesarean delivery reduces the need for additional uterotonic agents but does not affect the overall occurrence of major obstetric haemorrhage.”